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libco: riscv64: Add RISC-V64 Linux support #13

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4 changes: 4 additions & 0 deletions libco.c
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,10 @@
#include "arm.c"
#elif defined(__aarch64__)
#include "aarch64.c"
#elif defined(__riscv) && defined(__riscv_xlen) && \
__riscv_xlen == 64 && !defined(__riscv_abi_rve) && \
!defined(__riscv_float_abi_quad)
#include "riscv64.c"
#elif defined(__powerpc64__) && defined(_CALL_ELF) && _CALL_ELF == 2
#include "ppc64le.c"
#elif defined(_ARCH_PPC) && !defined(__LITTLE_ENDIAN__)
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223 changes: 223 additions & 0 deletions riscv64.c
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Original file line number Diff line number Diff line change
@@ -0,0 +1,223 @@
/*
libco.riscv64
license: public domain
*/

#define LIBCO_C
#include "libco.h"
#include "settings.h"

#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>

#ifdef __cplusplus
extern "C" {
#endif

#if defined(__riscv_float_abi_double) || defined(__riscv_float_abi_single)
#define LIBCO_RISCV64_HARD_FLOAT
#endif

typedef struct {
uintptr_t ra;
uintptr_t sp;
uintptr_t s[12];
#ifdef LIBCO_RISCV64_HARD_FLOAT
uint64_t fs[12];
uintptr_t fcsr;
#endif
void (*entrypoint)(void);
} co_context;

typedef char co_context_ra_offset[(offsetof(co_context, ra) == 0) ? 1 : -1];
typedef char co_context_sp_offset[(offsetof(co_context, sp) == 8) ? 1 : -1];
typedef char co_context_s_offset[(offsetof(co_context, s) == 16) ? 1 : -1];
#ifdef LIBCO_RISCV64_HARD_FLOAT
typedef char co_context_fs_offset[(offsetof(co_context, fs) == 112) ? 1 : -1];
typedef char co_context_fcsr_offset[(offsetof(co_context, fcsr) == 208) ? 1 : -1];
#endif

static thread_local co_context co_active_context;
static thread_local cothread_t co_active_handle;

#if defined(__riscv_float_abi_double)
#define LIBCO_RISCV64_SAVE_FLOAT \
" fsd fs0, 112(a1)\n" \
" fsd fs1, 120(a1)\n" \
" fsd fs2, 128(a1)\n" \
" fsd fs3, 136(a1)\n" \
" fsd fs4, 144(a1)\n" \
" fsd fs5, 152(a1)\n" \
" fsd fs6, 160(a1)\n" \
" fsd fs7, 168(a1)\n" \
" fsd fs8, 176(a1)\n" \
" fsd fs9, 184(a1)\n" \
" fsd fs10, 192(a1)\n" \
" fsd fs11, 200(a1)\n" \
" csrr t0, fcsr\n" \
" sd t0, 208(a1)\n"
#define LIBCO_RISCV64_RESTORE_FLOAT \
" fld fs0, 112(a0)\n" \
" fld fs1, 120(a0)\n" \
" fld fs2, 128(a0)\n" \
" fld fs3, 136(a0)\n" \
" fld fs4, 144(a0)\n" \
" fld fs5, 152(a0)\n" \
" fld fs6, 160(a0)\n" \
" fld fs7, 168(a0)\n" \
" fld fs8, 176(a0)\n" \
" fld fs9, 184(a0)\n" \
" fld fs10, 192(a0)\n" \
" fld fs11, 200(a0)\n" \
" ld t0, 208(a0)\n" \
" csrw fcsr, t0\n"
#elif defined(__riscv_float_abi_single)
#define LIBCO_RISCV64_SAVE_FLOAT \
" fsw fs0, 112(a1)\n" \
" fsw fs1, 120(a1)\n" \
" fsw fs2, 128(a1)\n" \
" fsw fs3, 136(a1)\n" \
" fsw fs4, 144(a1)\n" \
" fsw fs5, 152(a1)\n" \
" fsw fs6, 160(a1)\n" \
" fsw fs7, 168(a1)\n" \
" fsw fs8, 176(a1)\n" \
" fsw fs9, 184(a1)\n" \
" fsw fs10, 192(a1)\n" \
" fsw fs11, 200(a1)\n" \
" csrr t0, fcsr\n" \
" sd t0, 208(a1)\n"
#define LIBCO_RISCV64_RESTORE_FLOAT \
" flw fs0, 112(a0)\n" \
" flw fs1, 120(a0)\n" \
" flw fs2, 128(a0)\n" \
" flw fs3, 136(a0)\n" \
" flw fs4, 144(a0)\n" \
" flw fs5, 152(a0)\n" \
" flw fs6, 160(a0)\n" \
" flw fs7, 168(a0)\n" \
" flw fs8, 176(a0)\n" \
" flw fs9, 184(a0)\n" \
" flw fs10, 192(a0)\n" \
" flw fs11, 200(a0)\n" \
" ld t0, 208(a0)\n" \
" csrw fcsr, t0\n"
#else
#define LIBCO_RISCV64_SAVE_FLOAT
#define LIBCO_RISCV64_RESTORE_FLOAT
#endif

asm(
".text\n"
".p2align 2\n"
".globl co_switch_riscv64\n"
".type co_switch_riscv64, @function\n"
"co_switch_riscv64:\n"
" sd ra, 0(a1)\n"
" sd sp, 8(a1)\n"
" sd s0, 16(a1)\n"
" sd s1, 24(a1)\n"
" sd s2, 32(a1)\n"
" sd s3, 40(a1)\n"
" sd s4, 48(a1)\n"
" sd s5, 56(a1)\n"
" sd s6, 64(a1)\n"
" sd s7, 72(a1)\n"
" sd s8, 80(a1)\n"
" sd s9, 88(a1)\n"
" sd s10, 96(a1)\n"
" sd s11, 104(a1)\n"
LIBCO_RISCV64_SAVE_FLOAT
" ld ra, 0(a0)\n"
" ld sp, 8(a0)\n"
" ld s0, 16(a0)\n"
" ld s1, 24(a0)\n"
" ld s2, 32(a0)\n"
" ld s3, 40(a0)\n"
" ld s4, 48(a0)\n"
" ld s5, 56(a0)\n"
" ld s6, 64(a0)\n"
" ld s7, 72(a0)\n"
" ld s8, 80(a0)\n"
" ld s9, 88(a0)\n"
" ld s10, 96(a0)\n"
" ld s11, 104(a0)\n"
LIBCO_RISCV64_RESTORE_FLOAT
" ret\n"
".size co_switch_riscv64, .-co_switch_riscv64\n"
".previous\n"
);

void co_switch_riscv64(cothread_t handle, cothread_t current);

static void co_entry_trampoline(void)
{
co_context *context;

context = (co_context *)co_active_handle;
context->entrypoint();
abort();
}

cothread_t co_active(void)
{
if (!co_active_handle) {
co_active_handle = &co_active_context;
}

return co_active_handle;
}

cothread_t co_create(unsigned int size, void (*entrypoint)(void),
size_t *out_size)
{
size_t context_size;
size_t stack_size;
size_t total_size;
co_context *context;

context_size = (sizeof(co_context) + 15) & ~(size_t)15;

if ((size_t)size > SIZE_MAX - 15) {
return 0;
}

stack_size = ((size_t)size + 15) & ~(size_t)15;
if (stack_size > SIZE_MAX - context_size) {
return 0;
}

total_size = context_size + stack_size;
context = (co_context *)malloc(total_size);
if (!context) {
return 0;
}

memset(context, 0, context_size);
context->ra = (uintptr_t)co_entry_trampoline;
context->sp = (uintptr_t)context + total_size;
context->entrypoint = entrypoint;

*out_size = total_size;
return (cothread_t)context;
}

void co_delete(cothread_t handle)
{
free(handle);
}

void co_switch(cothread_t handle)
{
cothread_t previous_handle;

previous_handle = co_active();
co_active_handle = handle;
co_switch_riscv64(handle, previous_handle);
}

#ifdef __cplusplus
}
#endif